JPS58194041A - Negatively chargeable liquid developer used for printing plate material - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic negatively chargeable liquid developer usable for manufacturing a printing plate high in resolution and superior in etching resistance, etc., by using a fluorine-contg. polymer as a negative charging controller. CONSTITUTION:A photoconductive layer is imagewise exposed to form an electrostatic latent image by the electrophotographic method, developed to form a toner image, and after fixation, it is etched to elute the nonimage parts of the photoconductive layer, thus preparing a printing plate. The negatively chargeable liquid developer used at that time is composed of (a) colorant, (b) coating agent, such as alkyd resin, ethylene type resin, or acrylic resin, (c) liquid carrier, and (d) a negative charging controller, preferably, fluorine-contg. polymer, such as polytetrafluoroethylene, polychlorotrifluoroethylene, or polyvinyl fluoride. By using said developer, a printing plate high in resolution is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a negatively charged liquid developer, and more particularly to a negatively charged liquid developer for printing original plates used in the process of manufacturing printing plates by electrophotography.

Conventionally, lithographic printing plates have been made by coating a printing substrate with a photosensitive resin, but the sensitivity is extremely low compared to silver salt photosensitive materials and electrophotographic photosensitive materials. For this reason, in order to expose a printing original plate using a photosensitive resin, a silver salt film produced by the Photo-X plate making method is brought into close contact with the printing original plate, and strong ultraviolet light is exposed. However, in recent years, with the aim of saving labor, resources, and processes, the photolithography process of producing a silver halide complex photographic light-sensitive material ψ that is developed with a silver salt lithium film (lithium chloride developer) has been omitted. A plate-making method has emerged in which a printing plate is manufactured by directly printing a manuscript onto a printing plate.

An electrophotographic process L is known in which a printing plate is produced by directly photographing a document using an electrophotographic method.

For example, Special Publication No. 37-17162, Special Publication No. 38-69
No. 61, Japanese Patent Publication No. 39-12703, etc., a photoconducting layer is provided on a roughened aluminum plate, and a toner image is formed by charging, exposing, and developing using a normal electrophotographic method. A method is described in which a printing plate is manufactured by dissolving the image area (the area to which no toner is attached) with an alectic solution. Furthermore, JP-A-54-144203 discloses a toner i formed on a zinc oxide photoreceptor by an electrophotographic method.
A method is described in which ik1g# is transferred to a transfer printing plate having an epoxy resin layer provided on an aluminum plate, heat-fixed, and then the epoxy resin layer in the non-image area is eluted with a solvent to produce a lithographic printing plate. In these conventional techniques, since a dry developer is used when obtaining a toner image by electrophotography, there is a drawback that image resolution is poor. In general, when obtaining a toner image by electrophotography, a wet developing method is characterized by far better resolution and image reproducibility than a dry developing method. However, in the electrophotographic method, which includes a ψ process in which the photoconductive layer in the non-image area is dissolved and removed after the toner image is formed and fixed (hereinafter referred to as etching), a useful wet developer is still not available. For example, Japanese Patent Application Laid-open No. 50-19510 describes the smell of a liquid developer to which soybean lecithin is added as a charge control agent or a liquid that does not contain a charge control agent in the electrophotographic process described above. Developers are used, but such liquid developers have poor dispersion stability of toner particles and are not practical.Also, after wet development is performed with a commercially available liquid developer to form a toner image, etching is not necessary. When manufacturing printing plates by performing
Adhering toner (portions marked with ~) is also easily eluted.

That is, the etching properties of the image area are poor, and a useful printing plate cannot be obtained.

The object of the present invention is to use '1!' in an electrophotographic method. A liquid developer used in the production of printing plates that forms a gaseous residue image, develops it after image exposure, forms a toner image, and then performs an etching process after fixing to elute and remove the photoconductive layer in the non-image area. The object of the present invention is to provide a negatively charged liquid developer for a printing original plate, which makes it possible to obtain a printing plate with high resolution.

Another object of the present invention is that the photoconductive layer in the image area exhibits extremely strong resistance to the etching agent in the etching process after fixing, and the 11111g# area does not dissolve out when using a negative charge for printing original plates. An object of the present invention is to provide a liquid developer.

Another object of the present invention is to provide a negatively charged liquid developer for printing original plates having excellent dispersion stability.

As a result of extensive research, the present inventors formed an electrical latent on a printing plate having a photoconductive layer on a support using an electrophotographic method, and after image exposure, developed it with a liquid developer to form a toner image. After fixing, the photoconductive layer in the non-image area is eluted,
A liquid developer used for manufacturing printing plates, comprising:
(a) a coloring agent, (b) a coating agent, (C) a negative charge control agent, and (d) a carrier liquid; and a fluorine-containing polymer is used as the negative charge control agent in (c) above. The inventors have discovered that the above object can be achieved using a negatively charged liquid developer for printing original plates, and have completed the present invention.

The present invention will be explained in detail below.

Examples of the fluorine-containing polymer used in the present invention include polytetrafluoroethylene, polyfluoroptrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polyfluoroalkyl vinyl ether, and polyfluoroptrifluoroethylene.
Homopolymers of fluorine-containing monomers, such as alkyl 7 acrylates, ethylene-tetrafluoroethylene copolymers, ethylene-tetrafluoroethylene copolymers, tetrafluoroethylene-vinyl chloride copolymers, or fluorine-containing monomers and other monomers. There is a copolymer with

As the coating agent used in the present invention, many known coating agents can be used. For example, a fluid resin, an acrylic resin, a methacrylic resin, a styrene resin, a vinyl chloride resin, a vinylidene chloride resin, an ethylene resin, a propylene resin, a rubber resin, or various natural resins are used. Incidentally, among these coating materials, ethylene resin gives the most preferable results for the purpose of the present invention.

Various pigments and dyes can be used as the colorant used in the present invention, and there are no particular limitations.

For example, carbon black, steel phthalcyanine, lid p
Cyanino green, malachite green.

--There are Damin, Victoria Blue, Oil Black, etc.

The carrier liquid used in the present invention has an electrical resistance value of 101
An organic solvent with a dielectric constant of 0Ωm or more and a dielectric constant of 3 or less, for example, n
- Pentane, isoparaffin, naphtha, casing, light oil, trifluoroethane, etc. are used.

In JP-A-54-25833, the above-mentioned fluorine-containing polymer is used, but the photoconductive layer is charged and exposed to form an electrical latent image, and the latent image is formed with a liquid developer. In the normal electrophotographic method, which cleans the developer remaining on the photoconductive layer after visualizing and transferring the developed image to a transfer material, liquid developer is used mainly to improve durability, transferability, and cleaning performance. It is not added as a charge control agent. Therefore, in this respect, the present invention is clearly different from the present invention, which uses a fluorine-containing polymer as a charge control agent, and the technology for obtaining a negatively charged solvent with excellent printing properties is unique to the present invention. be.

The quantitative ratio of the substances constituting the liquid developer used in the present invention is 0.5 to 10 t of colorant, 2 t of coating material per 1 t of carrier liquid.
．． It is preferable to use the charge control agent in a range of 0.01 to 0.5V.

Furthermore, other natural or synthetic polymer compounds may be added to the liquid developer of the present invention for the purpose of improving L1 fixing properties and dispersion stability.

The liquid developer of the present invention can be prepared by, for example, adding a colorant, a toner, and a fluorine-containing polymer to a carrier liquid, and then applying a ball mill, a sand mill, a colloid mill, an ultrasonic dispersion method, etc.
It can be manufactured by performing a dispersion operation.

The printing original plate treated with the liquid 5A developer according to the IMK of the present invention is one in which a photoconductive layer is provided on a conductive support such as an aluminum or ram plate. The photoconductive layer is a layer containing a photoconductor, and at least one of an inorganic or organic photoconductor and a photoconductive organic pigment is used as the photoconductor. A printing original plate is produced by dissolving or suspending the photoconductor in a solution containing a natural or synthetic polymeric substance and layering it on a conductive support by a known method. The printing original plate obtained in this way is subjected to a normal electrophotographic method.
After charging, exposure 12, development with the liquid developer of the present invention and fixing, and then etching the non-image area with a residue to produce a printing plate. In the above plate-making process, the light source for exposure (xenon lamp, halogen lamp, tungsten lamp, fluorescent lamp, Ar, He-Ne,
A semiconductor laser or the like is used. The above-mentioned fixing is an operation in which the toner particles in the image area are adhered or fused to the photoconductive layer to prevent the etching solvent that dissolves the non-image area from penetrating. Any method such as removing the electrically insulating liquid using a squeeze roller, room temperature air or hot air, or simultaneously removing the electrically insulating liquid as described above, or applying pressure or heating after removal may be used.

The etching solvent is appropriately selected depending on the photoconductor or binder resin s'#4 constituting the photoconductive layer. Regarding such plate-making methods, etc., reference may be made to Japanese Patent Application No. 56-124128, Japanese Patent Application No. 56-124129, etc.

When the liquid developer of the present invention is used for plate making and etching, the image area exhibits extremely strong resistance to the etching agent, and the image area will not be eluted. Furthermore, the obtained printing plate has high resolution and good image reproducibility.

Next, embodiments of the present invention will be described in detail, but the embodiments of the present invention are not limited thereto.

Example 1 The above composition was dispersed and homogenized using an ultrasonic disperser at room temperature. The obtained photosensitive liquid was applied onto a roughened aluminum plate to a film thickness of 5 μm to produce a printing original plate.

on the other hand.

The above mixture was dispersed for 24 hours using a magnetic pole, and 1 part by weight of this dispersion was added to 10 parts by weight of Isopar G with stirring to produce a liquid developer.

Next, the printing original plate is positively charged with a corona charging device,
Using a reflective positive light on the original and 110 20W fluorescent lamps as a light source, image exposure was performed through a lens system to obtain an electrostatic latent image, which was developed using the liquid MS agent described above. After heat fixing,
A printing plate was prepared by immersing the plate in an alkaline water bath consisting of sodium silicate and sodium silicate and etching the photoconductive layer in the non-image area. As a result, as shown in Table 1 below, a printing plate was obtained which had excellent etching resistance and excellent first-order resolution.

Example 2 The above mixture was treated in exactly the same manner as in Example 1 to obtain liquid 1.
A body@(& agent was produced. Next, using the printing original plate obtained in Example 1, it was negatively charged with a corona charging device, and then the manuscript was charged with a microfilm and a commercially available photographic enlarger was used. After photographing at a magnification of 16 times (area ratio), the film was developed using the liquid developer, dried in a dryer (air at room temperature), and immersed in a water bath consisting of sodium silicate and caustic soda. A printing plate was produced by removing the photoconductive layer in the non-image area.As a result, a printing plate with excellent etching resistance and excellent resolution was obtained as shown in Table 1 below.

Example 3 The above mixture was treated in exactly the same manner as in Example 1 to produce a liquid developer. Next, the printing original plate obtained in Example 1 was treated in the same manner as in Example 1 except that the liquid developer was used. As shown in Table 1 below, it had excellent etching resistance and improved resolution. An excellent printing plate was obtained.

Example 4 The above mixture was deposited on a roughened aluminum plate to a film thickness of 8 μm.
A printing original plate was manufactured.

First, the above mixture was treated in exactly the same manner as in Example 1 to produce a liquid developer. Next, using the above-mentioned printing original plate, processing was carried out in exactly the same manner as in Example 1 except that the above-mentioned liquid 5A developer was used, and as a result, a printing plate with excellent resolution was obtained.

In order to clarify the effects of the present invention, the results are shown in Table 1 along with the results of a comparative experiment.

Table 1 [Experimental Conditions] Fixing: Processed for 1 minute in audan at 100°C (other than Example 2).

Etching; P of 5DP-1 (manufactured by Konishiroku Photo Industry ■)
Use a 7-fold dilution of the current salary solution for S plate.

Dispersion stability of developer: The liquid developer was diluted 2 times.

Comparative Example 1 A printing plate was obtained by carrying out the plate-making process in exactly the same manner as in Example 1, except that U-BIXV3R) toner (powder toner, manufactured by Konishiroku Photo Industry ■) was used as the developer.

Comparative Example 2 The above mixture was treated in exactly the same manner as in Example 1 to produce a liquid developer. Next, a printing plate was obtained by performing a plate-making process in exactly the same manner as in Example 1 except that this liquid developer was used.

Comparative Example 3 The above mixture was treated in exactly the same manner as in Example 1 to produce a liquid developer. Next, a printing plate was obtained by performing a plate-making process in the same manner as in Example 4, except that this liquid developer was used.

Patent applicant Konishiroku Photo Industry Co., Ltd. Agent: Patent attorney Akira Sakaguchi (and 1 other person)

Claims (1)

[Claims] An electrical latent image is formed on a printing plate having a photoconductive layer on a support using an electrophotographic method, and after image exposure, it is developed with a liquid developer to form a toner image, and after fixing, the non-image area is A liquid developer used to bathe out a photoconductive sand layer to prepare a printing plate, the liquid developer comprising: (a) a colorant; (b) a coating;
A negatively charged liquid developer for a printing original plate, comprising C) a negative charge control agent and (d) a carrier liquid, and comprising a fluorine-containing polymer as the negative charge control agent (c).